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采用K2TiF6和KBF4混合盐原位反应法制备TiB2/7055复合材料,研究了稀土对复合材料铸态组织和力学性能的影响。结果表明:添加0.3%稀土可以显著细化复合材料的铸态组织,晶粒尺寸从200μm减小到40μm左右。同时,TiB2颗粒得到细化,其平均尺寸约为100 nm;TiB2颗粒在基体上的分布也更加均匀。经过480℃固溶60 min、120℃时效24 h后复合材料抗拉强度达到690 MPa,伸长率达到5.5%。
TiB2 / 7055 composites were prepared by K2TiF6 and KBF4 mixed salt in situ reaction. The effects of rare earth on the as-cast microstructure and mechanical properties of the composites were investigated. The results show that the addition of 0.3% rare earth can significantly refine the as-cast microstructure of the composites, and the grain size decreases from 200μm to 40μm. At the same time, TiB2 particles were refined with an average size of about 100 nm. The distribution of TiB2 particles on the matrix was also more uniform. After 480 ℃ solution for 60 min, the tensile strength of the composites reaches 690 MPa after 24 h aging at 120 ℃, and the elongation reaches 5.5%.